The history of D'Addario (pronounced 'dad dario') is one of a family business that can be traced back to the town of Salle in Italy. The town was known as a farming and string-making community, and records as far back as 1680 list a Donato D'Addario as a string-maker. Early in the 20th century, brothers-in-law Rocco and Carmine (later Charles) were carrying on this family tradition.
When popular music led to a rise in guitar players in the 1930s, the family began working with guitar manufacturers and individual musicians to produce made-to-order guitar strings. Similarly, after the development on nylon during World War II, the company began developing nylon strings to replace traditional sheep and pig gut strings.
Some younger members of the family, led by Charles' son John, broke away in 1956 to produce steel strings, which were becoming more and more popular. Charles had considered the market for steel strings too uncertain, but after finally being convinced of its viability, the two companies merged again in 1962. The company is still family owned and run, counting 13 members amongst its 1000 employees.